Study On Adsorption And Separation Of Caffeine&Tea Polyphenols From Instant Tea By-product With Macroporous Resins

In the commercial production of instant tea, the ultrafiltration is commonly usedin extraction of tea. And during this filter process, a certain amount of retention fluidcan be produced. In the next step,the retention fluid were re-dissolved and re-filtered,similarly retention fluid produced. And instant tea by-product is to be obtained bydrying the retention fluid of the second filter step. The by-product still contains someactive ingredients of tea, such as tea poly-phenols, caffeine. Recycling these activeingredients from instant tea by-product is not only benefit to company，but alsoprevents pollution to the environment.Alkali is usually used in re-dissolving process, as a result，a certain of saltgenerated. Thus desalination is needed before Macroporous resin adsorption. Theconductivity, the recovery of caffeine and tea polyphenols are considered to select thebetter desalting resin.In this paper, six products macroporous resins were used to adsorb staticlycaffeine and tea polyphenols in instant tea by-product, to test caffeine as the mainindicators, tea polyphenols as a secondary detection of the adsorption properties ofvarious resins, the results showed D101had a good staticly adsorption, followed bydynamic adsorption testing of the resin. In the dynamic test，three factors and threelevels of the orthogonal test was designed based on the adsorption velocity, solutionconcentration and solution temperature single-factor experiments to establish theoptimum parameters of adsorption: the adsorption velocity,solution temperature,concentration of caffeine and TP were1.5mL/min,60℃,0.08mg/mL and8.0mg/mL,respectively. Determine conditions of the adsorption after dynamic desorption test.Through the single-factor test of desorption velocity, ethanol concentration and theamounts of eluant and orthogonal test, the optimum parameters of dynamicdesorption are determined: desorption velocity,ethanol concentration and theamounts of eluant value were1.0mL/min,80%,4BV,respectively.In this condition,caffeine content increased from6%to23%, TP content increased from38.03%to60.87%, the yield reached16.85%.